This means that to migrate each name over from the previous registry, the name must be recreated as if from scratch - so, for example, if ‘foo.eth’ does not yet exist in the new registry, the owner of ‘eth’ must create it in the same fashion as if it were a new domain, by calling `setSubnodeOwner` (or the new `setSubnodeRecord`). Other top-level domain owners (eg, .luxe, .kred, .club and .art) will need to do this on behalf of their users, so those users can recover write access to their domains.